Recent advances in the identification of tumor antigens recognized by autologous T cells, and improved strategies to augment and monitor the anti-tumor immune response have provided novel immune-based modalities for the treatment of patients with cancer with potentially minimal toxicity and high specificity. The strategy of adoptive T cell therapy involves the isolation and ex vivo expansion of highly selected antigen-specific T cells and represents a precise and rigorous means of controlling the magnitude, specificity and phenotype of an intended immune response. The application of adoptive therapy to the treatment of patients with ovarian cancer, which in its advanced stages following primary therapy is generally incurable, was heralded by the identification of NY-ESO-1 as a potential T cell target antigen. NY-ESO-1 is a cancer-testis antigen that is expressed in 25% of ovarian tumors, limited in expression to adult testis, and is immunogenic, capable of inducing both humoral and cellular responses. In Specific Aims 1 and 2 of this project, we propose to evaluate the use of adoptively transferred CD4 and CD8 T cells targeting NY-ESO-1 for the treatment of patients with ovarian cancer in clinical studies that evaluate the toxicity, duration of in vivo numeric and functional persistence, and anti-tumor activity of adoptively transferred T cells. Potential obstacles to more effective therapy will be addressed by analysis for the emergence of antigen-loss variants and an evaluation of the process of 'antigen spreading'. The clinical trials proposed in this project will serve as a platform for the translational evaluation of future potential ovarian target antigens that include antigens evaluated in Specific Aim 3. In Aim 3, ovarian antigens previously identified by our group by serologically-directed recombinant expression cloning (SEREX) will be evaluated as potential T cell target antigens. In this way, potential obstacles to a broader and more effective application of T cell therapy can be addressed by expanding both the repertoire of potentially therapeutic target antigens and the pool of eligible patients.